SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17738d9cfe631114d9bf72b498bd15118a7889553f73e57deeb96a6f80ac33fb' 
  AND token = 'cU3etstvqi4jsMBXscykzid89hdNWPDE3fqi+WGxFJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}